The Gynecologic Oncology Group (GOG) is the foremost multidisciplinary cooperative clinical trial research group devoted to the study of gynecologic malignancies. Since its inception in 1970, the GOG has been a recognized leader in the development of new forms of treatment and has relied on Phase III trials as the design to identity new standards of care for cancers of the female genital tract, in particular ovarian carcinoma, carcinoma of the uterine cervix, and endometrial carcinoma. Supporting that major activity are the concerted efforts of special studies committees focusing on translational research, developmental therapeutics, quality of life, and cancer prevention and control; and modality committees providing recent approaches and procedures in each of the relevant diagnostic and therapeutic disciplines. The GOG has an active, effective program in the study of new surgical and radiation approaches as well as new systemic agents. In patients with advanced ovarian cancers, GOG studies have defined the current standard of care of cytoreductlve surgery followed by systemic therapy including a taxane and a platinum compound. Current studies seek to improve on this standard with trials of intraperitoneal therapy, targeted agents, and maintenance therapy for those in complete remission. In patients with carcinoma of the cervix, GOG studies have identified new chemotherapeutic agents and combinations for use in the setting of advanced or recurrent disease and have set the standard of care for earlier stage cervix cancer (FIGO stages IB-IVA) as concurrent, cisplatin-based chemoradiation. Current and planned investigations will explore better chemoradiation combinations and the role of targeted agents such as bevacizumab. In patients with endometrial carcinoma, GOG studies have changed the paradigm for the management of advanced or recurrent disease by defining roles for chemotherapy in this difficult patient population. The GOG also has an active effort in less common gynecologic malignancies including uterine sarcomas, gestational trophoblastic disease, germ cell tumors of the ovary, vulvar cancer, among others. Making all of this effort to improve the standard of care possible is an active and extensive effort to identity new approaches through developmental therapeutics and to develop a better understanding of the biology of these malignancies through an active and extensive translational research program. After more than 39 years, the GOG continues to be foremost in developing new strategies for managing these cancers.